Shock absorber



Jan. 29, 1935.

' E. F. ROSSMAN( SHOCK ABSORBER Filed Jan. 21, 1952 3 7 4 S 4/ s um, my 0 4 @s 6 v. 2/ a m e, m/ 7 3\ 0 3 w d 7 4 4@ /l 2f,

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Patented Jan. 29, 1935 UNITED` STATES snocx ABsoRBEn vEdwin F. Rossman, Dayton, Ohio, assgnor, by

mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Dela- Application January 21,

15 Claims.

v absorber capable of controllingboth the compression and the rebound movements of the vehicle springs, said shock absorber having a pressure regulated device for controlling the restriction to the iiuid flow in response to spring compression and rebound movements.

` Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodi ment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a fragmentary side view of a vehicle chassis with a'shock absorber embodying the present invention attached thereto. The road wheels of the chassis are omitted for the sake of clearness Fig'. 2 is a longitudinal sectional view taken through the center of the shock absorber.

Fig. 3 is a detail view of the pressure regulated valve.

Referring to the drawing, the numeral designates the frame of the vehicle which is supported upon the vehicle axle 21 by spring`22. The shock absorber designated as a whole by the numeral 23 comprises a'casing 25 which is attached to the frame 20 of the vehicle in any suitable manner. This casing provides a uid reservoir 26 and a cylinder 27 in communication with said reservoir. The ends of the cylinder are closed by cylinder head caps 28 and v29, respectively. Within the cylinder there is provided a piston 30 which forms the spring compression control chamber 31 at the one end of the cylinder and the spring rebound control chamber 32 at the opposite end of the cylinder. The piston operating arm 33 extends into a central recess in the piston, said piston operating arm being secured to or formed integral with the rocker shaft 34 which is -journalled in the casing 25 in any suitable manner, one end of said shaft extending outside the casing and having the shock absorber operating arm 35 provided thereon. The free end of this shock absorber operating arm35 is swivelly attached to one end of the link 36, the opposite end of said link being swivelly secured to a member 37 which is anchored to the axle 21 by the clamp 38.

The casing 25, as shown in Fig.`2, has a recess 40 which may be termed a valve chamber. This valve chamber is in communication with the spring compression control chamber 31 and the spring rebound control chamber 32 through the ducts 41 and 42, respectively.

. Chamber 40 receives the valve block 43 and the 1,982, serial No. 587,901

head-block 44 which are maintained in spaced e relation within said chamber'. 40 by a spacing Washer 45. Both these blocks 43 and 44.are retained within the valve chamber 40 by the retainer cap 46 which is screw threaded into the outer end of .the recess or valve chamber 40. Suitablefpackings 47, 48 and 49'are provided to prevent iiuid leaks. The block 43 has a recess 50 in which the valve 51 is slidably supported,

said valve 51 having an annular groove 52 fcr` purposes to be described.

A recess 53 in one'end of the valve receives a spring 54, one end of Awhich engages'the inner end of the recess 50 in block 43. vThis spring 54 yieldably urges the valve 51 into engagement with the head block 44. It may bevseen inboth Figs.`

2 and 3 that valve 51 has lugs 55 extending from its lower end, or more specically'the end engaging the head block 44 whereby passagesare provided between this end of the valve and the head block when said valve is resting'upon said head block. An oriiice 56 provides communication between the recess 53 in the valve 51 and the space between valve 51 and the head block 44, this orifice being of a predetermined size. While valve 51 is in normal position, that is, While it is resting upon the head block 44, it shuts off communication be' tween passages 57 and 58 inthe block 43 which passages communicate with the ducts 41 and 42, respectively. Thus'it may bes'aid thatvalve 51 normally shuts off'communication between the spring compression and spring-'rebound control chambers'Sl and 32, respectively. f

-In the block 43 there is provided a passage 60 communicating with chambers 61Jand 62 which chambers are connected with the passages 57 and 58 respectively in said block. rEach chamber 61 and '62 contains an adjustablevalve lseat member 63 having a ball check valve 64 yieldably urged against it. These valves areso arranged that no fluid may iiow from their respective passages 57 or 58 into the passage 6 0, but fluid may iiow from said passage 60 past these respective valves 64 into ltheir respective block passages 57 and 58. Passage 60 is inY communicationwiththe valve con-v taining recess 50 of block 43 through an opening 66. The space 70 between the head block 44 and the valve block 43is in communication with both valve block passages 57 and'58. The passage 72 connects said'spacef' with the passage 57 and a threaded opening in the head block 44 receiving a recessed stop screw 76 which contains a spring 77 engaging the respective ball check valves 74v or 75 to urge it upon the seat. The inner tubular end 78 Y ally aligning with the passages 72 and 73, each of each stop screw 76 is adapted to act as a stop upon ,which the respective v.ball check valve rests when operatedby iluidv pressure. In orderlto increasethe valve movement 'from'its seat the cap screw must be screwed outwardly in the headfcap, thereby increasing the distance from the tubular stop portion 78 of the cap screw and the .fvalveisea't of the respective valve and .thus increasing the size ingmemberzSarerotated clockwise, pressure will .be .exerted .uponzthefluid-with-in' thespring comipressionfcontrollchamber 31 and 'thus-th-isrflud Y.

ic-rred form,-it is to be understood' that-'otherfor-ms vmight be lado'pted, all coming within 'the-scope `of the claims which (follow.

xwill abe :forced from said 1 chamber through .the v.ductiiL :ItacannotowdirectlyzfromfductvlilIto aduct 42.0fithe sprin'greboundzcontrol chamber, fior 'valve 5l 'normally shuts :oi Vcommunication fbetween .these i t-wo i ducts. The f fluid cannot :flow from duct 41 and its communicatingvalvefpas- -sage'HL-past'theslalve 64 into'the passage, for .'Yalver64r isconstructediand arranged onlyfto dischargedntothepassage 57. `.".IE-he uid:;pressure, zh'owever, :may be 1 directed :against :the Vvalve 74,

v:rnovildgsaid valvefawaylfrom its seattowardffand against-the stoplprovidedfbyethe tubular end 17:8 of

the :screw-.cap 76 therebyito-establish .anforice-.of

a .predetermined @size between valve 74 :and :its

.valve seat, :said :size being controlled -by 'the =ad ijustment of `.thestopscrew 76. Now therluidfwill -howiinto the-.space fmtbetween ythe-valve block-'43 :and the i'head `.block 44, pressure being exerted lupon thellowerendfo-fthevalve 5'1. Thefluid'will low `from f-said fspace 70- .through the :restricting "orifice-'56 finto .the space: inside -the' .valve contain- --ingrrecess-m thence A,through the opening 66 into ithe lmassage ".60, thence through :the member T63 imovinglitsvalve 64ifromthe`.seat and-establishing a low into ithe;passage\58`which communicates .withwductf42 ands-the :rebound-t'controlf chamber 32. Y.Guinee H56 is :considerably jsmaller in :fluid -ow capacity than iszthe-nrificeprovirled between valve Maand its .seat-thusvandifferentialfpressure is set up'vwithin the space 70 vwhich-:diiferential:pressure :overcomes :theveffect y'of fspringl54 `to maintain the 'valveflin its normaliposition so thatrinrespcnse to .this differential pressure valve51 :will be .moved upwardly .fand bring its Iannular groove 52'into :communication with .the transverse passages 57 1and :58 -in the valveblock 43 so that fnow 'a 4'restrictedifluid flowiwill beiestablisheddirectly, between :ducts -41 zand -42 through the passages 57 .and 58 respectively, incommunication with each .other across-ther .annular groove 52 of valve 51.

f illhegreaterthe-luidrfiow established bythe-orifice -`presented betweenvalve v174 and its seat, the greater -will ybe the dinerential pressure upon `the fvalve 1.51 to -move :it-.out :of fnormalposition and :thustthe less -will bethe'restriction tothe flow of fluid established between `ducts 41 `and .42 respec- 'illhefsameoperationbecomeseffective when the rpistnno is moved towardthexright in response to .rebound 'movements-of ythe vehicle springs-22. In instance thefluid pressure will be :established ,against `valve 715,.'moving Ait from its seat `to estabflishatow intethespace 7.0, thencethroughforice irand' epening into:thepassage 60, thence-.past Yvalue nuto -theftransversc )passage 557. this case the differential pressure will also move the valve 51.from .its normal 4position to establish a restricted flow between ducts 42 and41.

`The orifice presented by valves`7`4 and '75 may be adjusted by turning stop screws 76. These screws are accessible when the cover cap 46 is removed from the casing. The head cap 44 ts snugly `v/ithin the recess of the casing so that 'removal'f'c'ap '46'w'ill not permit the valve assemblyltddropfrom the recess nor fluid to leak from the casing. -The valves 64 are adjustable also, but in this case it is necessary to remove the --`entire"valve' assembly. The adjustment of valves 64..however, is seldom necessary, for these valves do not control the differential pressure which operates valve -5-1to establish' its'variable restriction to the direct flow of'iluidbetweenY compression. chambers 31 and 32.

While ther'form of embodiment of'the'prescnt invention as herein disclosed, constitutes a `pre- -What is-claimed'is'as follows:

1. A hydraulic shock-'absorbericomprising, Iin:H

combination, a casing-providing za vfluid reservoir and.A fluid fpressure chambers; mean'sfforfcirculatwing -iiuid between said fchambers; control Emeans normally shutting oifsa-idfluid circulation; -and iiuid iiowI orices adaptedto establish a differential iiuid pressure against said control `means lto move it for establishing fluid circulationfbetween vtheuchamlcers.

2. A--hydraulic shock absorber comprising, in

combinationf-a-casing providing `a-fluid reservoir, fluid displacement means and -Viiuid compression chambers communicating with each other controlimeans yieldably .urged knormally to s hut off communication between --said chambers; and

means of different fluid flow capacity -adapted to establish a differential pressure against said-controlimeansor moving -it to establish saidcommunication -bet/Ween vthe compression ichambers.

3. IA control'device for ahydraulic shock-ab- .sorberfhavinga:casingproviding a'uidreservoir,

chambers therein a duct connectingsaid chambers; meanszyieldably urged'toclose theduct; and `fluid -ow controlling V*means yin communication -Withsaid duct adapted, in vresponse to iluidpres- :sure-'in'either compression chamber, to establisha differential fluid pressure for moving said `yieldable 4means to-establish -a -variably --restricted flow of -fluid through lthe duct.

5. :A hydraulic shock absorber comprising, -in combination, a casing providing a cylinder; 'a piston lin said 'cylinder lforming -tvvo `compression chambers therein; `a duct 'connecting said -chafmbers; a valve yi'eldably urged to 'close the duct; and different sized, constant flow oricesin 'cornmunication with ysaidduct adapted, in response to fluid pressures in the-compression chamber to 'establish 'a dineren-tial fluid .pressure l'agaiI-ist `the valve whereby said valve will be moved to establish a variably restricted flow of fluid through the duct.

6. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder; a piston in said cylinder forming two compression chambers therein; a duct connecting said chambers; a valve yieldably urged to close the duct, said valve having an orifice; means providing communication between the compression chambers through said orice; and fluid flow control devices in said means, cooperating with said orice to establish a diierential fluid pressure for moving the valve to open the duct and establish variably restricted iiows of uid therethrough.

7. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder; a piston in said cylinder forming two compression chambers therein; a duct in the casing adapted to provide communication between said chambers; a valve yieldably urged into said duct to close it, said valve having an oriiice; and means of greater fluid flow capacity than said orice, adapted to deliver fluid from the duct portions on either side of the valve to one side of the valve orifice for moving the valve to establish variably restricted flows of fluid through the duct.

8. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder, a piston in said cylinder forming two compression chambers therein; a valve chamber in the casing formmg a part of the main communication between the compression chambers; a valve in the valve chamber yieldably urged to shut off said main communication between the compression chambers; ducts adapted to direct fluid pressure from each compression chamber against one end of the valve for moving said valve to open the main communication between said compression chambers; and a constant fluid flow orifice in said valve for controlling the fluid pressure from either compression chamber upon said valve.

9. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder; a piston in said cylinder forming two compression chambers therein; a valve chamber in the casing in communication with each compression chamber; a valve in the valve chamber yieldably urged to shut oi communication between the compression chambers and the valve chamber; ducts providing for the application of fluid pressure from each compression chamber against one end of the valve for moving said valve to open communication between said compression chamber; adjustable means in said ducts for varying the huid flow therethrough; and a iiuid flow orifice in said valve, in communication with said ducts and normally of lesser fluid iiow capacity than said ducts.

10. A hydraulic shook absorber comprising, in combination, a casing providing a cylinder; a piston in the cylinder forming two compression chambers therein; a valve vchamber in communication with both of said compression chambers; a valve in the valve chamber; a spring engaging one end of the valve and normally urging the valve to shut off communication between the compression chambers and the valve chamber; an orifice providing a restricted connection from one end of the valve to the other; ducts providing communication between the respective compression chambers and the endof the valve opposite that engaged by the spring; and adjustable ball-check valves in said ducts adapted to establish constant fluid flows in one direction only said flows being of substantially greater volume than that established by the valve orifice.

11. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder; a piston in said cylinder forming two compression chambers therein, said chambers being in communication with each other through a passage in the casing; a valve normally extending into said passage to shut off said communication between the compression chambers, said valve having an ori-ce providing for the transfer of fluid from one end of the valve to the other; ducts providing communication between the portions of the passage on each side of the valve, said ducts each communicating with a respective end of the valve; and valves in said ducts certain of which establish constant fiuid liows from the respective passage portions on each side of the valve into said valve orifice, others establishing a flow of uid from said valve orice into said passage portions.

12. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder; a piston in said cylinder forming two compression chambers therein, said chambers being in communication with each other through a passage in the casing; a valve yieldably urged into said passage to divide it intov two non-communicating portions; ducts providing by-passes between said passage portions and around the valve; an orice in said valve adapted to establish a flow of iiuid through the valve transversely of the passage; means in one duct for establishing a oonstant flow of fluid from either passage portion to one end oi the valve orifice only, said iiuid flow being of a greater volume than the Iiow established by said orifice; and means in the other duct for establishing only ows of iluid from the valve orifice into one of the passage portions.

13. A hydraulic shock absorber comprising, in combination, a casing providing a cylinder in which a piston forms two compression chambers in communication with each other by a duct in one of the shock absorber members; a valve normally closing said duct; and means for divert-v ing uid pressure from each of said chambers against said valve, said means including diiferential fluid flow control devices for regulating the fluid pressure upon said valve to move it to openv the duct in accordance with the fluid pressure in said duct.

14. A hydraulic shock absorber having a normally closed fluid ilow control device, and means including a spring-loaded member and an orice in the iiuid ow control device having differential fluid ow capacities for establishing a inean fluid pressure for actuating said device toward open position in accordance with the pressure of the fluid flow to be controlled.

l5. A hydraulic shock absorber having a chamber in which pressure is exerted upon a fluid; a normally closed pressure release valve for controlling the ilow of fluid from said chamber; and devices having differential fluid iiow capacities for establishing a mean uid pressure against said valve to open it in accordance with the fluid pressure in said chamber.

EDWIN F. ROSSMAN. 

